金华北山洞穴滴水氢氧稳定同位素的特征及气候意义

Characteristics and palaeoclimatic significance of hydrogen and oxygen isotopes of drip water in Beishan cave of Jinhua

为揭示洞穴滴水氢氧同位素特征及气候意义,对金华北山双龙洞和二仙洞的大气降水、洞穴滴水、岩石裂隙水、地下河水、洞外泉水进行了7~9个月的连续监测和分析。结果表明:1地表水的氧同位素变化幅度大于洞穴水,说明其对外界环境的响应比洞穴水更敏感。2洞穴滴水的氢氧同位素值并没有与大气降水线完全吻合,大部分投影在雨水线下,这反映了地表的蒸发作用以及包气带含水层对滴水存在着显著的调蓄作用。3滴水的δ18OV-SMOW具有干湿季变化特征,旱季偏正,雨季偏负,但滴水δ18OV-SMOW值滞后2~3个月。本研究结果可为重建金衢盆地的古环境提供依据。

In order to reveal the characteristics and palaeoclimatic significance of hydrogen and oxygen isotopes of cave drip water,the paper analyzed and measured the atmosphere precipitation,cave drip water,rock fissure water,river ground water and spring water in both Double Dragon Cave and Erxian Cave for 7 ~ 9 consecutive months.The results showed that:1 the variation of δDV-SMOWand δ18OV-SMOWof surface water is greater than that of cave water,which responses to external environment more sensitively.2 the δDV-SMOWand δ18OV-SMOWvalues of drip water is not completely coincided with MWL.Most of the projects are below MWL which indicates that the evaporation of land surface and the aquifer of storage water have obvious regulation function on drip water performed.3 the δ18OV-SMOWvalue of drip water possesses the characteristics of temporal variability of dry and wet seasons.It is lower in summer rainy season,while it is higher in winter dry season,but the lag time is about 2 to 3 months.This results can provide the basis for reconstructing paleoenvironment in Jinhua-Quzhou basin.